The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
The present invention relates to methods, apparatuses and compositions for improving visibility, more particularly for improving visibility of objects or locations by implementing visually enhancing materials.
There are numerous settings wherein it is desirable to enhance the visibility of associated markings or demarcations. For instance, emergency signage should be sufficiently visible, under exigent circumstances, so as to provide guidance for locating exits, pathways or escape routes. Ladders, barriers, roadway markings, etc., should be clearly defined at construction sites. Aircraft landing aids should be appreciable to the pilot above under various adverse conditions.
Photoluminescent (sometimes abbreviated xe2x80x9cluminescentxe2x80x9d) materials, photoreflective materials (sometimes abbreviated xe2x80x9creflectivexe2x80x9d) and retroreflective materials have each been used effectively in a variety of applications for signage and similar delineative purposes. See, e.g., the following United States patents, each of which is hereby incorporated herein by reference: Anders U.S. Pat. No. 5,874,491 issued Feb. 23, 1999; Palazzotto U.S. Pat. No. 5,822,120 issued Oct. 13, 1998; Kozak et al. U.S. Pat. No. 5,873,187 issued Feb. 23 1999; Bilingsley U.S. Pat. No. 5,812,317 issued Sep. 22, 1998; Murakami et al. U.S. Pat. No. 5,811,174 issued Sep. 22, 1998; Hedblom U.S. Pat. No. 5,777,791 issued Jul. 7, 1998; Nakajima U.S. Pat. No. 5,777,790 issued Jul. 7, 1998; Moriyama et al. U.S. Pat. No. 5,770,111 issued Jun. 23, 1998; Tanaka et al. U.S. Pat. No. 5,759,671 issued Jun. 2, 1998; Hachey et al. U.S. Pat. No. 5,750,191 issued May 12, 1998; Yonetani U.S. Pat. No. 5,698,301 issued Dec. 16, 1997; Murayama et al. U.S. Pat. No. 5,686,022 issued Nov. 11 1997; Wyckoff U.S. Pat. No. 5,670,209 issued Sep. 23, 1997; Anders U.S. Pat. No. 5,665,793 issued Sep. 9, 1997; Kozak et al. U.S. Pat. No. 5,660,497 issued Aug. 26, 1997; Ishihara U.S. Pat. No. 5,607,621 issued Mar. 4, 1997; Bernard U.S. Pat. No. 5,592,330 issued Jan. 7, 1997; Brown et al. U.S. Pat. No. 5,586,787 issued Dec. 24, 1996; Wyckoff U.S. Pat. No. 5,576,097 issued Nov. 19, 1996; Hachey et al. U.S. Pat. No. 5,571,362 issued Nov. 9, 1996; Kozak et al. U.S. Pat. No. 5,516,227 issued May 14, 1996; Murayama et al. U.S. Pat. No. 5,424,006 issued Jun. 13, 1995; Hachey et al. U.S. Pat. No. 5,417,515 issued May 23, 1995; Zampa et al. U.S. Pat. No. 5,415,911 issued May 16, 1995; Bradshaw U.S. Pat. No. 5,268,789 issued Dec. 7, 1993; Hedblom U.S. Pat. No. 5,227,221 issued Jul. 13, 1993; Bailey et al. U.S. Pat. No. 5,064,272 issued Nov. 12, 1991; Dejaiffe U.S. Pat. No. 4,983,458 issued Jan. 8, 1991; Kuney U.S. Pat. No. 4,957,335 issued Sep. 18, 1990; Wood et al. U.S. Pat. No. 4,772,511 issued Sep. 20, 1998; Lange U.S. Pat. No. 4,758,469 issued Jul. 18, 1988; Lange U.S. Pat. No. 4,564,556 issued Jan. 14, 1986; Quon U.S. Pat. No. 4,546,042 issued Oct. 8, 1985; Trachtenberg U.S. Pat. No. 4,250,646 issued Feb. 17, 1981; Jack et al. U.S. Pat. No. 3,989,775 issued Nov. 2, 1976; Bingham U.S. Pat. No. 3,700,305 issued Oct. 24, 1972.
Each kind of visual enhancement material has something different to offer. Retroreflectors are especially effective when light which is impinging thereon is coming from the direction of the observer, as is the case, for example, of a nighttime driver when the light from his motor vehicle""s headlights impinges on a traffic sign. Reflectors are especially effective when light which is impinging thereon is coming from a different direction from that of the observer and reflects in the direction of the observer, as is the case, for example, of a nighttime driver when the light from his motor vehicle""s headlights misses a traffic sign, but the light from another source (or other sources) impinges on the traffic sign. Luminescents (e.g., phosphorescents, fluorescents and bioluminescents), which derive energy from one or more non-thermal sources and emit their own light, are especially effective under near dark or very dimly lit conditions. Typically, a conventional visual enhancer will be adapted to a particular application in terms of certain anticipated conditions and circumstances; nevertheless, the conventional visual enhancer may still prove deficient on a significant number of occasions or on a too frequent basis.
Moreover, there are certain situations wherein safety is only limitedly furthered by visual indication, albeit such visual indication is imbued with photoluminescent, photoreflective or retroreflective characteristic. For example, in many emergency situations lighting is obscured by smoke or chemicals, thus reducing or thwarting the effectiveness of the photoluminescent, photoreflective or retroreflective indicator. Floors, steps (e.g., stair treads), ladderways, aircraft landing areas, etc., are contexts wherein safety can be augmented by affording manual and/or pedal tactility of a particular indicator, in addition to visibility thereof.
In view of the foregoing, it is an object of the present invention to provide signs, markers and like articles which are optimally visible when impinged upon by light under a variety of deficient visual conditions.
Another object of the present invention is to provide such signs, markers and like articles which are readily appreciable both visually and tactilely.
A further object of the present invention is to provide methods of making such signs, markers and like articles.
It is another object of the present invention to provide compositions, for being applied to objects in liquid form as a coating therefor, wherein the applied compositions are optimally visible when impinged upon by light under a variety of deficient visual conditions.
A further object of this invention is to provide such compositions wherein the applied compositions are readily appreciable both visually and tactilely.
Another object of this invention is to provide methods of making such compositions.
A further object of the present invention is to provide auxiliary devices for adhering to objects so as to be optimally visible when impinged upon by light under a variety of deficient visual conditions.
It is another object of this invention to provide such auxiliary devices which are readily appreciable both visually and tactilely.
A further object of this invention is to provide methods of making such auxiliary devices.
In accordance with many embodiments of the present invention, an article or device comprises a particulate-containing matrix. The particulate-containing matrix includes: a resinous matrix material; a plurality of retroreflective spheres; a plurality of photoreflective pigments; and, a plurality of photoluminescent pigments. The resinous matrix material contains the retroreflective spheres, the photoreflective pigments and the photoluminescent pigments. The resinous matrix material has a matrix surface portion which is exposable to light from an exterior source. The retroreflective spheres generally are disposed protrudingly at the matrix surface portion. The photoreflective pigments and the photoluminescent pigments generally are disposed beneath the matrix surface portion. According to some such inventive embodiments, the particulate-containing matrix further includes a plurality of abrasive elements (e.g., abrasive grit such as but not limited to aluminum oxide, silica and carbide). The resinous matrix material contains the abrasive elements. The abrasive elements generally are disposed protrudingly at the matrix surface.
In accordance with many inventive embodiments, a method for visually enhancing an object comprises: providing a resinous matrix material which is in an uncured liquid state; mixing photoluminescent pigments in the resinous matrix material; providing photoluminescent pigments; providing photoreflective pigments; mixing the photoluminescent pigments in the resinous matrix material; mixing the photoreflective pigments in the resinous matrix material; depositing the resinous matrix material on the object (the resinous matrix material being in an uncured liquid state, and containing the photoluminescent pigments and the photoreflective pigments); curing the resinous matrix material while the resinous matrix material is upon the object (the resinous matrix material being in an uncured liquid state, and containing the photoluminescent pigments and the photoreflective pigments); providing retroreflective spheres; and, distributing the retroreflective spheres onto (on top of) the resinous matrix material during (at some time or times in) the curing. According to some such embodiments, the inventive method further comprises providing abrasive elements, and distributing the abrasive elements onto (on top of) the resinous matrix material during (at some time or times in) the curing.
The inventive mixing, in the uncured liquid resinous matrix material, of the photoluminescent pigments and the photoreflective pigments, can be performed together and/or separately. That is, the photoluminescent pigments and the photoreflective pigments can be mixed with each other and then aggregately mixed into the uncured liquid resinous matrix material; and/or, the photoluminescent pigments and the photoreflective pigments can be sequentially or alternatingly mixed, in any order, directly into the uncured liquid resinous matrix material.
The present invention provides a versatile, uncomplicated visual enhancer which efficaciously combines the attributes of reflection, retroreflection and luminescence. The inventive principles are practically universal in application, since diverse lighting conditions are accounted for by the invention. This invention affords continued visibility following illumination with visible light, as well as improved visibility under variously illuminated or nonilluminated conditions.
Inventively featured is a blend of retroreflective, reflective and luminescent pieces contained in a resinous matrix characterized by a unified, single-matrix configuration. The inventive matrix embraces retroreflective, reflective and luminescent properties in the visible range of frequency. The retroflective pieces are protrusively distributed in the matrix. The reflective and luminescent pieces are nonprotrusively distributed in the matrix. The present invention""s combined, discrete implementation of photoluminescent material entities, photoreflective material entities and retroreflective material entities has not been observed elsewhere.
According to many inventive embodiments, the three kinds of microentitiesxe2x80x94viz., retroreflective spheres, photoreflective fragments and photoluminescent fragmentsxe2x80x94are densely dispersed throughout the matrix, with the retroreflective spheres predominating and partially protruding at the top surface of the matrix (i.e., the surface facing the light source). In typical inventive practice, the inventive matrix is effectively stratified wherein the retroreflective elements define an upper stratum, and the photoreflective elements and photoluminescent elements define a lower stratum.
When light hits the inventive particulate-containing matrix, the three kinds of microentities respond to the light in collective and complementary fashion, thus rendering the particulate-containing matrix highly visible under poorly lit conditions. The photoluminescent elements store visible light from previous illumination events. In addition, the combined implementation of the three kinds of microentities serves to diversify the angularity of reflection of the matrix; in other words, light which hits the matrix will reflect back to the source as well as reflect in numerous xe2x80x9cnon-retroxe2x80x9d directions.
The terms xe2x80x9cretroreflectivexe2x80x9d and xe2x80x9cphotoreflectivexe2x80x9d as used herein are distinguishable. As used herein, the term xe2x80x9cretroreflectivexe2x80x9d refers to reflection of light off a surface: in a retrodirectional way. A retroreflective object is a specially contrived object which receives a light ray and turns the light ray around, sending the light ray back to the source of the light ray. The term xe2x80x9cphotoreflectivexe2x80x9d (or xe2x80x9creflectivexe2x80x9d) has been commonly used, in a general sense, to connote reflection of light off a surface. As used herein, the term xe2x80x9cphotoreflectivexe2x80x9d is meant to be differentiated from the term xe2x80x9cretroreflective.xe2x80x9d That is, a photoreflective object, as intended herein, is one which reflects light in an ordinary way, i.e., not in a way which is retrodirectionally contrived. A xe2x80x9cphotoreflectivexe2x80x9d object, as intended herein, is characterized by lacking the retrodirectional quality of a xe2x80x9cretroreflectivexe2x80x9d object. Typically, a xe2x80x9cphotoreflectivexe2x80x9d object will be so structured or configured as to generally entail the normal, uncomplicated effect of direct reflection from the object""s exterior surface, wherein the angle of light incidence equals the angle of light reflection with respect to such surface. Hence, as intended herein, *xe2x80x9cretroreflectorsxe2x80x9d and xe2x80x9cphotoreflectorsxe2x80x9d are mutually exclusive.
Many inventive embodiments utilize two types of photoreflective material, viz., xe2x80x9cdiffuselyxe2x80x9d reflective material and xe2x80x9cspecularlyxe2x80x9d reflective material. Utilization of both types of pigments enhances the inventive visual (especially, retroreflective) effect by angularly diversifying the reflection of light. Some inventive embodiments utilize reflective pigments which are diffuse reflective pigments only or which are specular reflective pigments only.
Typical embodiments of the present invention combine at least the three attributes of retroreflectivity, photoreflectivity and photoluminescence. Such embodiments are useful for affording visual cues to the observer in a variety of applications, such as the following: emergency signage for location of exits, pathways, escape routes, etc.; ladders; steps; roadway markings (e.g., for poorly lit roadways); unlit disabled vehicles; damaged aircraft (e.g., lacking onboard lighting); aircraft landing aids. These and other demarcation purposes provide visual cues with or without impingement by emergency lighting or headlights (as in the case of roadway demarcation), and also tactile cues for use in emergency situations where lighting is obscured by smoke.
Some inventive embodiments afford additional versatility by combining the attribute of abrasiveness (frictionality) with the three attributes of retroreflectivity, photoreflectivity and photoluminescence. Hence, such inventive embodiments are xe2x80x9cvisual-tactile,xe2x80x9d combining visual enhancement with tactile enhancement. According to such inventive embodiments, frictional (abrasive) elements are protrusively distributed in the matrix at its surface. Thus, the inventive matrix typically contains two kinds of particulate matter which are partially exposed (i.e, retroreflective elements and abrasive elements) and two kinds of particulate matter which are not exposed (i.e., photoreflective elements and photoluminescent elements); in effect, the inventive matrix is stratified wherein the retroreflective elements and abrasive elements define an upper stratum, and the photoreflective elements and photoluminescent elements define a lower stratum.
The inventive quality of tactility is useful, for instance, in the following applications: on floors (for non-slippage as well as for imparting cues by foot-feel); on ladderways (for hand tactility as well as foot tactility); and,on aircraft landing areas (where non-skid properties contribute to safety of personnel and equipment, particularly under wet and oily conditions common to such areas as aircraft carrier landing decks and helipads).
The present invention can be embodied in various modes, including the following: (i) an applique tape having robust adhesive qualities; (ii) a resinous liquid, conventionally applied as a paint or coating; and, (iii) a flat or formed composite object (or group of objects) which is structurally sound, such as a plate, lettering or shaped signage (e.g. directional arrows). Applique embodiments are particular useful for effecting xe2x80x9cquick-fixxe2x80x9d marking of ship decks and other structures (e.g. plylons). Inventive articles and devices can serve to communicate via characters, symbols, figures, pictures, arrows or other representative means. There are many possible embodiments and applications for inventive articles and devicesxe2x80x94for instance, a polymeric cover for a fire extinguisher; or, attachable (e.g., attachable to a ladderway) nonskid stair treads (e.g., made of a material such as a polyurethane matrix).
Through retroflection, reflection and photoluminescence, the inventive articles, devices and compositions improve visual detection thereof in the absence of normal lighting, or in diminished lighting, or in complete darkness. The present invention admits of numerous applications, some of which are aforementioned. A notable application of this invention involves rescue missions. The portable lighting utilized by rescue crew may be unavailable or limited. Such lighting can be inventively supplanted, particularly by the efficient photoluminescence inventively provided.
Moreover, inventive embodiments having non-skid attributes are especially valuable when total visual obfuscation is brought about by smoke or other visual impairment. Such inventive embodiments impart information as to direction, object identification and location by tactile feel. In addition, such inventive embodiments afford increased safety from slippage, especially under wet and/or oily conditions.
Thus, the inventively combined effect of retroflection, reflection, fluorescence and tactility provides clearer cues for emergency escape, demarcation, object-location, etc., under extreme conditions of darkness, visual obfuscation and/or slipperiness. Such conditions are prevalent in diverse emergency and damage-control situations, such as associated with domestic building fires or exigencies aboard ships at sea. The present invention""s consolidation of the four attributes of retroflection, reflection, fluorescence and tactility is believed to be currently unavailable in the art.